There are known laser processing devices for welding or processing workpieces by guiding the laser beam emitted from a laser oscillator such as a gas laser or a solid-state laser through an optical fiber.
It is common to perform alignment between the laser oscillator and the optical fiber in order to enhance their coupling efficiency, thereby ensuring the laser beam power used for processing.
A well-known alignment technique is performed as follows. A laser beam from the laser oscillator strikes one end of the optical fiber through an optical member such as a condenser lens, and the power of the laser beam emitted from the other end is measured with, for example, a power meter. The position of the condenser lens is adjusted to maximize the power (e.g., Patent Literature 1).